Diaphragm pump



`Mmyls, 1934. w, CARTER 1,958,509

DIAPHRAGM PUMP Filed Feb. 18, 1953 H .I FIGLI i H l ,l

)I B D p V22;. A J

j z 3 K @a D F c 2 .f jg.. a /0 L2\ ,ffl L `9 f3 FIGZ gurl I I/vve/vToRWILLIAM C. CARTER Patented May l5, i193@ UNET f 2 Claims.

This invention relates to diaphragm pumps of re kind that are used forpumping a liquid from a source of supply to a consumption device inwhich the consumption of liquid from the pump is irregular, and upon thecomplete interruption of the consumption of liquid by said device, apressure is created which is exerted on the diaphragm of the pump inopposition to the means that imparts a discharge stroke or power stroketo the pump diaphragm.

I have herein illustrated my invention embodied in a fuel pump that isintended to be used for feeding gasoline or the like from a supply tankto the float chamber of the carburetor of an internal combustion engine,and which is equipped with a diaphragm operating mechanism thatcomprises a cam or other prime mover and a member or element acted uponby said prime mover and arranged to actuate or impart movement to thediaphragm or to a part of the diaphragm operating mechanism that actsdirectly on the diaphragm. I wish it to be understood, however, that myinvention is not limited to a diaphragm pump that is designedparticularly for pumping gasoline or the like; also that variou'schanges can be made in the construction of the diaphragm operatingmechanism herein described without departing from the spirit of myinvention.

One object of my present invention is to provide a practicable diaphragmpump of the general type or kind previously referred to, wherein themember or element operated on by the prime mover, is of such design orconstruction that it is not necessary to directly actuate the diaphragmby a spring, or interpose a spring between the diaphragm and the memberor element that is operated on by the prime mover, thereby producing apump in which the pressure or power pro duced by the diaphragm isconstant or uniform throughout the entire stroke of the diaphragm whenthe diaphragm is in normal operation.

Another object of my invention is to provide a diaphragm pump that isequipped with an inexpensive diaphragm operating mechanism which is ofsuch design or construction that the pump can be easily combined with orinstalled on an internal combustion engine or other apparatus equippedwith a prime mover that constitutes part ofthe diaphragm operatingmechanism of the pump.

Other objects and desirable features of my invention will be hereinafterpointed out.

Figure l of the drawing is a vertical longitudinal sectional View of adiaphragm fuel pump constructed in accordance with my present invention;and

Figure 2 is a horizontal sectional view, taken on the line 2--2 ofFigure 1.

In the accompanying drawing which illustrates (Ci. 10S-38) the preferredform of my invention, A designates the diaphragm of the pump, which ispreferably composed of either one or a plurality of layers of fabrictreated with a substance that will render the fabric impervious togasoline or water, without making it brittle or inflexible, whichdiaphragm may be disposed either vertically or horizontally. Thediaphragm A is arranged `so as to form one wall of a pumping chamberinto which liquid fuel is drawn when said diaphragm flexes in onedirection, and from which said fuel is discharged when said diaphragmiiexes in the opposite direction, the said pumping chamber being formedby a cavity in a casting B that constitutes the body portion of the pumpand which is supported by a housing member C that is herein illustratedas being attached to the crank case D of an internal combustion engine.An inlet pipe E that leads from a source of supply of fuel delivers fuelto a fuel reservoir F in the body portion B of the pump, and a dischargepipe G that is attached to said body portion leads to the float chamberof a carburetor (not shown). An inlet valve H is provided for admittingfuel to the pumping chamber a: from the fuel reservoir F, and adischarge valve I is provided for governing the escape or passage of thefuel from the pumping chamber :c into the discharge pipe G.

The operating mechanism for the diaphragm A comprises a prime mover J,such, for example, as a cam arranged inside of the crank case D of theengine, a spindle or other part K attached in any suitable or preferredmanner to the center of the diaphragm, and an element or memberdesignated as an entirety by the reference character L in Figure l,arranged between the prime mover J and the spindle K for reciprocatingsaid spindle, so as to move the diaphragm A back and forth. In the formof my invention herein illustrated the element L consists of a leverrockably mounted or pivotally mounted on a horizontally-disposed pin orshaft 1 in the housing member C, and provided at one end with abifurcated portion 2 that is embraced by anges 3 on the spindle K.The'other end portion of said lever L projects inwardly through anopening in the crank case, as shown in pigure 1, and is provided with afork or yoke 4 that receives the cam J which constitutes the prime moverof the diaphragm operating mechanism.

When the engine is in operation there are times when the discharge valveI ef the pump will remain closed while the prime mover J of thediaphragm operating mechanism continues in operation, as, for example,`when the float chamber of .the carburetor is full, and the head orcolumn of fuel in the discharge pipe G of the pump exerts sufficientback pressure on the discharge valve I to preventl it from beingunseated by the pressure in the pumping chamber In order that thediaphragm A may remain at rest at-such times, or, in other words, inorder that said diaphragm and the diaphragm operating mechanism will notbe subjected to injurious strains when the consumption device with whichthe pump is used is not consuming or drawing' fuel from kthe pump, therockable element or lever L- is so constructed that under certainconditions one part of said rockable element, i. e., the right hand partthat is associated with the prime mover J, will rock on the fulcrum pin1 without imparting movement to the left hand part of said rockablemember L that is attached to the spindle K on the diaphragm. Thisresultor effect can be obtained in various ways without departing fromthe spirit of my invention, but I prefer to construct the lever orelement L from two sections'L' and L2 that are rockably mounted on thesupporting shaft or pivot pin 1, and join or connect said sections L andL2 together by a friction joint which is of such a character or naturethat under certain conditions said two sections will rock together ormove in unison, and under other conditions or different conditionsthesection-L actuated by the prime mover J can move independently of andrelatively to the section L2. As shown in Figure 2. the section L' isprovided at its inner end .with

a disk shaped portion 5 `through which the suptogether with suflicientforce or pressure to causev the section L2 to normally move with thesection L and co-operate with same to form a lever that is pivotallysupported intermediate its ends. In the pump herein illustrated thesprings 8 are formed by substantially disk-shaped resilient membersprovided with spring fingers 8a that exert an inward thrust on thedisk-shaped portions 7 of the section L2 which said springs 8 embrace,the said springs 8 being mounted on the supporting shaft 1 between thedisk-shaped portions 7 of the section L2 and parallel wall portions 9 onthe housing member C.

In order that the section L2 of the rockably element L will be sure torock or move with the positively actuated section L -when the element Lrocks in a direction to impart a suction stroke (downward stroke) to thediaphragm A, but will be free to'lag or stop when the element L rocks inthe reverse direction to impart a discharge stroke (upward stroke) tothe diaphragm if the discharge of fuel from the pumping chamber a: isinterrupted, a contractile spring M is attached to the sections L and L2in such a manner that when the section L rocks upwardly (looking atFigure 1 the spring M will exert pressure on the section L2 inadirection tending to cause the friction joint to exert more pull on thediaphragm, as is necessary on the suction stroke, and when the section Lrocks downwardly or in the reverse direction, said spring M will causethe friction'joint to exert less upwand push on the diaphragm, as isnecessary on the discharge stroke. In other words, there should be apressure of approximately four to six pounds bringing the liquid intothe pumping chamber and only a pressure of approximately one to twopounds forcing the liquid out of the pumping chamber. Accordingly, whatthe spring M subtracts from the discharge pressure it adds to thesuction stroke. I have herein illustrated the spring M as being attachedat one end to a lug 10 on the outer section L of the rockable element L,and being attached at its opposite end to a cross pin 1l carried by lugs12 on the inner section L2 of the rockable element L. As previouslyexplained,

when the pump is in normal operation, i. e., when the carburetor isdrawing iuel from the pump, the two sections L and L2 of the rockablemember L move in unison, but if the discharge of fuel from the pumpingchamber :l: is interrupted, the section L2 is capable of coming to restwhile the section L continues in operation, due to the friction joint orfriction connection between said sections. In this way I overcome theobjections incident to the use of a spring to directly actuate thediaphragm of the pump, without, however, imparting a positive stroke tothe diaphragm, and I produce a pump in which the force or pressurecreated by the diaphragm is maintained practically constant throughoutthe entire discharge stroke of the diaphragm. In addition toaccomplishing the highlyl desirable result previously described, thefriction joint of the rockable element L facilitates the installation ofthe pump on an internal combustion engine or other apparatus providedwith a cam or the like that constitutes the prime mover of the diaphragmoperating mechanism, due to the fact that saidv lfriction joint permitsthe two sections of 'the rockable element L to move sufficientlyrelatively to each other to cause the outer section L' to adapt itselfto the prime mover J, even though there is a slight mal-alignmentbetween the prime mover and the housing member C on which the rockableelement L is mounted.

Having thus described my invention, what I claim as new and desire tosecure byLetters Patent is:

l. A diaphragm pump provided with a diaphragm for causing liquid to bedrawn into and discharged from a pumping chamber, aprime mover and alever for transmitting movement from said prime mover to said diaphragm,said lever comprising two sections provided with overlapping portionsthrough which the fulcrum of the lever passes, means for frictionallyconnectingsaid overlapping portions, and a spring that co-acts with saidsections for increasing the tendency of said sections to move in unisonduring the suction stroke of the diaphragm, and to permitv relativemovement between said sections during the discharge stroke of thediaphragm.

2. A diaphragm pump provided with a diaphragm for causing liquid to bedrawn into and discharged from a pumping chamber, a spindle attached tosaid diaphragm, a prime mover, a housing lor supporting member, a leverpivotally mountedV on said housing and provided with two.-relativelymovable rockable sections, one of which is joined to saidspindle and the other arranged in engagement with said prime mover, afriction means for transmitting movement from the prime mover section tothe spindle section, and a spring combined with said sections forexerting a pull on said spindle section in a direction tending tocauseit to move with the prime mover section, during the suction str okeof' the diaphragm.

WILLIAM C. CARTER.

